Powergated

Powergated is a term used in semiconductor design to refer to a technique for reducing power consumption in integrated circuits. It involves selectively turning off power to parts of a chip that are not currently in use. This is achieved through the use of special "power gating cells" that act like switches, controlled by a power management unit. When a block of the chip is idle, its power supply can be disconnected, preventing leakage current from flowing and thus saving energy.

The primary benefit of power gating is significant power reduction, especially in applications where certain functionalities are used intermittently. This is particularly important for battery-powered devices like smartphones and laptops, where extending battery life is a key design goal. By minimizing static power consumption, power gating contributes to lower overall energy usage.

Implementing power gating involves careful consideration of several factors. The design must ensure that the blocks can be powered up and down quickly enough to meet performance requirements. Additionally, special techniques are needed to handle the "state retention" of these blocks, so that when power is restored, they can resume operation without losing their previous configuration or data. This often involves using techniques like level shifters and isolation cells to manage the voltage transitions and prevent unintended behavior in neighboring circuits. The process of integrating power gating requires thorough simulation and verification to ensure its effectiveness and reliability.